This 31-month supplement to Sustaining Women's Smoking Cessation Postpartum (Project PANDA) will design, implement, and evaluate an intensified intervention for pregnant women who were unable to stop smoking with minimal assistance. The substudy is a population-based experiment with White, Black, and Hispanic pregnant women whose continued smoking makes them ineligible for randomization into the parent study. It is unique in focusing on heavier, more addicted pregnant smokers. PANDA research sites and protocols offer a special opportunity for a low cost test of a disseminable intervention which this project team is uniquely qualified to design and implement. The new intervention, One- to-One, will use telephone counselors to assess the counselee's stage in the change process and give stage-appropriate messages, using established techniques of motivational interviewing. Between the two counselor calls spaced 10 days apart, counselees will receive personalized written feedback and suggestions. The primary aim, increasing quitting during pregnancy, will be assessed by unobtrusive urine samples taken during prenatal visits in the ninth month and identified only by study group. A series of postpartum interviews with subsample cotinine validation will be used to examine the second important aim, reduction of infant smoke exposure. A combination of messages, peer modeling, and support will help women sustain cessation after delivery and eliminate smoking around the baby. Project PANDA videotapes and newsletters already contain these messages and require only minimal supplementation to be used with the One-to-One experimental group, regardless of their success in quitting in pregnancy. As in Project PANDA, the assessments will be separated from the experiment by enrolling subjects in a university-sponsored study of new mothers' health practices and baby care and by presenting the program as usual care by the health care site. The substudy results will 1) demonstrate the effectiveness of the intensified program in boosting rates of prenatal smoking cessation and reducing infant smoke exposure from all sources and 2) contribute longitudinal data on change processes involved in smoking cessation and maintenance for this important group of heavy committed smokers experiencing a critical life transition.